ANISOTROPIC ENHANCEMENT OF FLUX-PINNING IN Y-BA-CU-O THIN-FILMS BY SUBSTRATE MEDIATED DEFECT CONTROL

YBa2Cu3O7-x, (YBCO) thin films have been grown on vicinal SrTiO3(001) single crystals. The films show a pronounced anisotropic resistivity a nd flux pinning properties in the substrate plane. UHV scanning tunnel ling microscopy and transmission electron microscopy have been used to investigate the substrate surface, film morphology and the growth ind uced defect structure. The anisotropy is caused by planar defects gene rated via self-organization of the YBCO which lead to an exceptionally large critical current density up to 8 x 10(11) A m(-2) at 4.2 K. The results demonstrate the possibility of a controlled enhancement of th e critical current by tailoring the growth induced defect structure.